POSTing takes quite some time on my MSI MS6151 (Intel 440bx chipset). It takes about 10 seconds for it to show anything on screen, it doesn't automatically skip the memory test, despite having "quick power on self test" enabled in BIOS. Then it takes like 10 seconds to detect each IDE device, being an HDD and a DVD drive.

This is how the system behaves on cold boot. When rebooting in Windows, at least the memory test will be skipped, everything else still takes some time.
BIOS is the latest and was patched with the rom.by BIOS patcher to correctly handle UDMA modes. But I don't think that is the issue since this already happened before flashing the BIOS.

Specs:
MSI MS6151
P3 1100/100
256GB of RAM
Geforce4 Ti 4600
Voodoo 2 SLI
AWE64

Once Windows loaded up, the system runs rock solid. I installed the MSI board as a replacement for my ASUS P2B-F, which was giving me trouble. The ASUS had lighting fast boot times, so not sure what is going on with the new board.